在MongoDB中搜索范围？
要搜索范围，sort()与limit()结合使用。让我们创建一个包含文档的集合-
> db.demo665.insertOne({"Value":10});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea1bf1424113ea5458c7d08")
}
> db.demo665.insertOne({"Value":15});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea1bf1b24113ea5458c7d09")
}
> db.demo665.insertOne({"Value":55});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea1bf1e24113ea5458c7d0a")
}
> db.demo665.insertOne({"Value":25});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea1bf2324113ea5458c7d0b")
}
> db.demo665.insertOne({"Value":20});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea1bf2b24113ea5458c7d0c")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo665.find();
这将产生以下输出-
{ "_id" : ObjectId("5ea1bf1424113ea5458c7d08"), "Value" : 10 }
{ "_id" : ObjectId("5ea1bf1b24113ea5458c7d09"), "Value" : 15 }
{ "_id" : ObjectId("5ea1bf1e24113ea5458c7d0a"), "Value" : 55 }
{ "_id" : ObjectId("5ea1bf2324113ea5458c7d0b"), "Value" : 25 }
{ "_id" : ObjectId("5ea1bf2b24113ea5458c7d0c"), "Value" : 20 }以下是在MongoDB中搜索范围的查询-
> db.demo665.find({Value:{$lte:30}}).sort({Value:-1}).limit(2);这将产生以下输出-
{ "_id" : ObjectId("5ea1bf2324113ea5458c7d0b"), "Value" : 25 }
{ "_id" : ObjectId("5ea1bf2b24113ea5458c7d0c"), "Value" : 20 }